It is general practice when building sun-lit plant houses, commonly termed glass houses, to simply construct a frame which carries a series of glass panes and it accepts light generally from all directions, and control of the amount of light reaching the internal of such a glass house being then purely by artificial shade means applied at the time they are required by the owner.
It is also known to construct such shade houses of wooden slats or to use slats to protect against too much sunlight passing through the glass.
The objects of the present invention are to provide an improved form of plant house which will have an effect such that the amount of sunlight admitted into the structure will be governed by the position of the sun in summer and in winter, whereby the required conditions in the plant house will be automatically adjusted according to the position of the sun in summer and winter.